from __future__ import annotations

import sqlite3
from pathlib import Path
from typing import Optional

from app.core.config import settings


def get_connection(db_path: Optional[Path] = None) -> sqlite3.Connection:
    path = db_path or settings.alarm_db_path
    path.parent.mkdir(parents=True, exist_ok=True)
    connection = sqlite3.connect(path)
    connection.row_factory = sqlite3.Row
    return connection


def _alarm_event_columns(connection: sqlite3.Connection) -> list[str]:
    rows = connection.execute("PRAGMA table_info(alarm_event)").fetchall()
    return [str(row["name"]) for row in rows]


def _ensure_alarm_event_schema(connection: sqlite3.Connection) -> None:
    expected_columns = [
        "id",
        "event_time",
        "line_code",
        "event_type",
        "event_code",
        "event_value",
        "content",
    ]
    current_columns = _alarm_event_columns(connection)
    if not current_columns:
        return
    if current_columns == expected_columns:
        return

    connection.execute("ALTER TABLE alarm_event RENAME TO alarm_event_legacy")
    connection.execute(
        """
        CREATE TABLE alarm_event (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            event_time TEXT NOT NULL,
            line_code INTEGER NOT NULL DEFAULT 0,
            event_type INTEGER NOT NULL DEFAULT 0,
            event_code INTEGER NOT NULL DEFAULT 0,
            event_value INTEGER NOT NULL DEFAULT 0,
            content TEXT NOT NULL
        )
        """
    )

    legacy_columns = set(current_columns)
    if {"time", "content"}.issubset(legacy_columns):
        connection.execute(
            """
            INSERT INTO alarm_event (event_time, line_code, event_type, event_code, event_value, content)
            SELECT
                time,
                CASE
                    WHEN typeof(no) IN ('integer', 'real') THEN CAST(no AS INTEGER)
                    WHEN trim(COALESCE(no, '')) GLOB '[0-9]*' AND trim(COALESCE(no, '')) <> '' THEN CAST(trim(no) AS INTEGER)
                    ELSE 0
                END,
                0,
                0,
                0,
                content
            FROM alarm_event_legacy
            """
        )
    connection.execute("DROP TABLE alarm_event_legacy")


def init_db() -> None:
    with get_connection() as connection:
        connection.execute(
            """
            CREATE TABLE IF NOT EXISTS alarm_event (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                event_time TEXT NOT NULL,
                line_code INTEGER NOT NULL DEFAULT 0,
                event_type INTEGER NOT NULL DEFAULT 0,
                event_code INTEGER NOT NULL DEFAULT 0,
                event_value INTEGER NOT NULL DEFAULT 0,
                content TEXT NOT NULL
            )
            """
        )
        _ensure_alarm_event_schema(connection)
        connection.commit()